ERBB2 and neoplasm: Whether treated with chemotherapy plus single or chemotherapy plus dual anti-HER2 therapy, patients with IHC 3+ tumours had a significantly higher pCR rate than those with the IHC 2+/HER2 amplified tumours (pCR rate in chemo+anti-HER2-single, 50.0% in IHC 3+ versus 19.4% in IHC 2+/HER2 amplified; p < 0.001) (pCR rate in chemo+anti-HER2-dual, 59.3% in IHC 3+ versus 17.6% in IHC 2+/HER2 amplified; p = 0.01).